Mix dry ingredients in your microwave-safe mug with a fork, add wet ingredients, mix well until smooth (making sure to get in all the flour around the bottom edge), add add-ins. My favorite add-ins for the chocolate cake are crushed peppermint candy or a couple of tablespoons of peanut butter. For the vanilla cake, try chocolate chips or raspberry jam--or both. Then nuke on high for about 70 seconds or until done. You'll need to do a few to test your microwave and see which power setting and timing work best. It's a terrible sacrifice, making and eating all those test cakes, but you'll manage to cope somehow.